1. Field of the Invention
The present invention generally relates to a semiconductor device and a production method for manufacturing such a semiconductor device, and more particularly relates to a power metal oxide semiconductor field effect transistor (MOSFET) device featuring a high breakdown voltage and a low ON-resistance, and a production method for manufacturing such a power MOSFET device.
2. Description of the Related Art
As a power MOSFET device featuring a high breakdown voltage, a vertical-type power MOSFET device is well known. There is an ON-resistance as one of significant factors for evaluating this type power MOSFET device. Of course, the smaller the ON-resistance, the higher the evaluation of the vertical-type power MOSFET device. Nevertheless, as the ON-resistance becomes smaller, the breakdown voltage is lowered. Namely, the decrease of the ON-resistance is incompatible with the increase of the breakdown voltage.
In order to resolve this incompatible problem, a super-junction (SJ) type power MOSFET device has been developed, as disclosed in, for example, in JP-A-2001-298189 and U.S. Pat. No. 6,509,240 B2. According to the SJ type power MOSFET device, the decrease of the ON-resistance is compatible with the increase of the breakdown voltage, but a production method for manufacturing the conventional SJ type power MOSFET device is troublesome and costly, as discussed hereinafter in detail.